Pension And Post-Retirement Health Care Benefit Plans (Summary Of Net Periodic Benefit Cost) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Pension And Post-Retirement Health Care Benefit Plans [Abstract]
Service cost-benefit earned during the period	$ 241	$ 192
Interest cost on projected benefit obligation	2,104	2,120
Expected return on plan assets	(2,501)	(2,522)
Amortization of prior service cost	44	34
Amortization of actuarial loss	1,548	485
Net periodic pension cost	$ 1,436	$ 309